There exists a wide variety of air conditioners employed at premises and inside transportation means. The proposed inventive system though substantially differs from the known devices in several aspects indicated further below.
A patent U.S. Pat. No. 6,793,016 teaches an air-conditioning unit for blowing air into a passenger's compartment and cooling a vehicle's seat. The present inventive system, in contrast, provides the cooling and heating of the blown air by means of a heat exchanger wherein the blown air is heated or cooled by hot or cold coolant liquid generally used for cooling the vehicle's engine.
A system described in another patent—U.S. Pat. No. 6,938,431 deploys two exchangers: one for cooling, and another for heating. The present inventive system deploys only one heat exchanger for cooling or heating the coolant, which coolant is further used in other heat exchangers to provide cooling or heating for different regions of the vehicle's interior.
In U.S. Pat. No. 7,069,938, a refrigerant—water heat exchanger is utilized. The proposed system uses a refrigerant—coolant (antifreeze) heat exchanger. The antifreeze coolant cannot freeze and damage the system. The inventive system additionally provides both: heating and cooling by means of only one liquid-coolant.
An air conditioner taught in U.S. Pat. No. 5,287,708 is associated with a hydraulically driven refrigerant compressor operating all the time while the vehicle's engine runs. The proposed system includes a refrigerant compressor operating only when the coolant's temperature rises, and the compressor is turned off when the temperature drops to a certain amount.
Some of the currently known air conditioning systems for vehicles (e.g. U.S. Pat. No. 6,435,273, U.S. patent application Ser. No. 10/178,009, all entirely incorporated herein by reference) deploy a hot liquid contour, e.g. utilizing an engine coolant fed into at least one coolant/air heat exchanger to heat the air; and a refrigerant contour, e.g. utilizing a known refrigerant, fed into a refrigerant/coolant heat exchanger to cool the coolant that may further be used in the aforesaid at least one coolant/air heat exchanger to cool the air to a required temperature for the vehicle interior.
Yet, those system are not highly efficient at least for two reasons: a) the vehicle's main engine has to run all the time to provide power for the refrigerant contour, or heat for the coolant contour, which causes significant loss of energy and high level of pollution (e.g. when a bus driver is waiting for passengers while there are no passengers in the bus); b) the produced heat or cool air provides all passengers of the vehicle with the same air temperature, though different spots of each passenger's body may require different temperatures (e.g. the front of one passenger's body needs less cool air, but the back is sweating and requires more cool air, whereas another passenger does not need the conditioned air at all), and some regions of the vehicle's interior may not require the conditioned air (e.g. when the respective seats are empty).